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人们对YBa_2Cu_3O_(7-x)(YBCO)薄膜中第二相的行为进行了广泛的研究,结果表明:第二相的形成可以对YBCO薄膜的生长机制、超导电性能产生相当大的影响.扫描电镜揭示了第二相与超导薄膜表面形貌的关系:随着薄膜中Cu/Y和Ba/Y原子比减小,YBCO薄膜的表面粗糙度增大;而增加薄膜中的Cu含量,将导致薄膜表面形成细小的第二相CuO颗粒.最近,一些研究小组在脉冲激光沉积制备的YBCO薄膜中观察到了析出相Y_2O_3,CuO,Y_2CuO_5和
The behavior of the second phase in YBa_2Cu_3O_ (7-x) (YBCO) thin films has been studied extensively, and the results show that the formation of the second phase can have a considerable influence on the growth mechanism and superconductivity of the YBCO thin films. Electron microscopy reveals the relationship between the second phase and the surface morphology of the superconducting thin film. As the atomic ratio of Cu / Y and Ba / Y decreases in the film, the surface roughness of the YBCO thin film increases; while increasing the Cu content in the thin film, Leading to the formation of fine second-phase CuO particles on the surface of the thin films.Recently, some research groups have observed the precipitation of Y_2O_3, CuO, Y_2CuO_5 and Y_2O_4 in the YBCO films prepared by pulsed laser deposition